In U.S. Pat. No. 5,660,490, there is described a binder ring metal commonly referred to as a “twist-lok” metal. An advantage of this type metal is that it is relatively easy for a user to open by applying finger pressure to respective halves of a binder ring, typically near the respective ends of the ring halves where they join together to close the metal. The user then moves his or her fingers in a rotary or twisting manner to separate the ends of the halves. The opposite ends of the ring halves are connected to separate leaves which extend side-by-side beneath a cover portion of the metal. The leaves have swedges which are angled with respect to the leaves and the twisting movement of the upper portion of the ring halves causes the leaves to sufficiently flex so that an over center toggling action occurs and the binder rings remain open after the finger pressure is released.
A problem with previous twist-lok metals has been that they are prone to open when a binder in which they are installed is accidentally dropped. If a binder falls off a table, or is bumped out of a person's hands while they are carrying the binder, it often occurs that one or more of the binder rings spring apart, opening the binder. The person then must retrieve the binder and re-close the rings, hopefully without having lost any pages out of the binder. The present invention is directed to an improved twist-lok ring metal which is still easy to open, but which now does not inadvertently open when dropped, bumped, or otherwise subjected to a force.